1. Field of the Invention
This invention relates to cylindrical containers having an open end sealed by a removable and resealable closure.
2. Description of the Prior Art
Wide mouth cylindrical containers, such as well known metal, and more recently molded plastic, paint pails are commercially used in very high volumes and consequently must be readily fillable and sealable using automated filling and sealing equipment.
Also, such containers must have very reliable but removable and resealable end closures or lids which ideally can be conveniently removed without the need of special tools and can be resealed to protect remaining product contained within a container from contamination and/or deterioration.
These containers should be producible and useable at a cost which enables them to be disposable when the contents have been depleted. Additional features prior art container designs have often provided are stackability of one container upon the other and placement of containers in abutting side by side proximity to each other to minimize the space occupied by a plurality of containers during shipment, storage and when displayed on shelves at the point of sale.
Automated filling equipment was generally used to fill the well known prior art metal containers which had rigid annular open top ends and relatively rigid cylindrical walls to maintain a fixed height.
With the advent of the use of molded or otherwise formed plastic containers it became necessary to design the containers using either relatively expensive rigid injected blow molded plastics or using configurations which required structural features which extended beyond the conventional structural confines of the container to cause cost penalties and/or space storage penalties.
U.S. Pat. No. 3,566,946 shows a container formed of a molded resilient plastic having a Y-shaped rim which protrudes outside of the normal space occupying structure of the container.
U.S. Pat. Nos. 4,293,080; 4,308,970 and 4,349,119 each show molded plastic containers in which the open ends of the containers disclosed have a substantial molded single rim molded lip which coacts with a pair of structural elements on the closure to form a removable and resealable end closure. These constructions appear to place dominant structural rigidity in the lid rather than on the open end of the container and therefore do not maximize the efficiency of the container for use with automated filling equipment.